U.S. Pat. No. 4,452,948 describes a coating composition suitable for use as a glossy pigmented coating for a rigid substrate, particularly where hardening of the coating at ambient temperatures is required, for example as a vehicle refinishing paint. The coating composition comprises a hydroxy component having at least two free hydroxyl groups per molecule and an anhydride component having at least two cyclic carboxylic acid anhydride groups per molecule, at least one of these components being a film-forming polymer. The composition also includes a catalytically effective amount of amine groups for accelerating the curing reaction between the hydroxyl groups and the anhydride groups. The amine groups are preferably incorporated in the molecule of the hydroxy component. Tertiary amine groups are preferred although certain secondary amine groups, for example those containing tertiary alkyl groups such as polymerised units of t-butylaminoethyl methacrylate, can be used.
European Patent 73022 describes an anhydride-functional polyester and claims its use as a hardener for compounds having free epoxide, amine or hydroxyl groups. European Patent Application 282184 describes a grease-compatible, plasticiser-extended encapsulant for spliced electrical or optical cable comprising an anhydride-functionalised composition and a crosslinking agent such as a polyol, polyamine or polythiol.
European Patent Application 259172 describes a coating composition comprising an anhydride polymer containing at least two cyclic carboxylic acid anhydride groups and a polymer containing at least two functional groups reactive with anhydride groups. These reactive groups are selected from hydroxyalkylamino, hydroxyalkoxyalkylamino, hydroxy-substituted acyloxyalkylamino, hydroxy-substituted polyacyloxyalkylamino, mercaptoalkylamino and oxazolidino groups. One of the polymers comprises a flexible polymer chain selected from polyether, polyester, silicone, diene polymer, hydrogenated diene polymer, polyurethane, polyisobutylene and polyacrylate chains. The functional groups characteristic of that polymer are each present as a terminal group at the end of a flexible polymer chain. The cured coatings have increased resistance to impact and abrasion. The hydroxyalkylamino groups are preferably tertiary amino groups but can be secondary amino groups formed for example from the reaction of a primary amino group with an epoxide or from the reaction of a carboxy-tipped polymer with N-hydroxyethyl imine.